Pope Benedict XVI has sought to allay fears of a rigid, authoritarian papacy by promising, in his first broadcast Mass, to reach out to Catholics and other faiths.

Pope Benedict XVI has sought to allay fears of a rigid, authoritarian papacy by promising, in his first broadcast Mass, to reach out to Catholics and other faiths.

As questions continued to be asked about his wartime past, he also announced that his first papal visit abroad would be to his native Germany.

But in the Bavarian town of Traunstein, where Joseph Ratzinger studied during his early years, his past resurfaced in the form of a large black German eagle and swastika, stamped in black ink on a document dating from his school days. The document is proof of the new Pope's qualification as an anti-aircraft "helper" in the Second World War. It is still kept in his file at Traunstein's Chiemgau school.

"I would like to show you more of the file, but much of it is protected under Germany's data-protection law. So I'm afraid I'm not allowed to," Klaus Kiesel, the school's director, said yesterday.

Little is known of the Pope's role during the Nazi era. Documents show that he served in an anti-aircraft unit near Munich and he also seems, briefly, to have been a member of the Hitler Youth movement.

In a pre-recorded interview with Bavarian state radio yesterday, Ratzinger was keen to play down this aspect of his past. "My brother was forced to join the Hitler Youth, but fortunately I was too young to have to do so," he told his interviewer.

Yet in interviews with school teachers, Traunstein residents and Catholic churchmen yesterday, evidence emerged to show that the Pope was indeed a participant in the Nazi war effort - albeit a very reluctant one.

The son of a rural Bavarian police officer, Ratzinger was six when Hitler came to power in 1933. His father, also called Joseph, was a staunch Catholic and an anti-Nazi.

Ratzinger was born in the Bavarian town of Marktl am Inn, close to the Czech border. But in 1937, his father retired and the family moved to Traunstein, a staunchly Catholic town of 23,000 close to Hitler's Bavarian mountain retreat on the nearby Obersalzburg. He was sent to the town's St Michael's Catholic seminary and attended Traunstein's humanistic gymnasium, a grammar school now renamed the Chiemgau School. During this time, the young Ratzinger acquired, among other passions, a taste for the literature of Hermann Hesse, in particular the seminal novel, Steppenwolf.

Father Thomas Frauenlob, who runs the Traunstein seminary which Ratzinger still regularly visits, said that the young man was fortunate to have been admitted: "In the 1930s the seminary in many ways shielded the boys from Nazi ideology," he said. "His family knew right from wrong and they could cope."

Yet while attending Traunstein school, the young Ratzinger was clearly exposed to Nazi influences. Several of the teachers were party members. "There was clearly an attraction in the party's emphasis on sport and athletics. I was young and I was tempted," Ratzinger said in his interview. "It was when the Nazis made it clear to me that they condemned Christianity because it had its roots in the despised Jewish faith that I realised their creed was nothing for me," he said.

In1941 Ratzinger was nevertheless forced to join the Hitler Youth because, in that year, the Nazis made membership of the organisation compulsory. He was 14 at the time. However, he quickly won a dispensation on account of his training at the seminary.

Yet two years later, at the age of 16, he was unable to dodge compulsory military service. He was sent to Munich to undergo training as a "flak helper", and became one of the thousands of young men drafted into the army during the closing stages of the war. Soon afterwards, he was dispatched to the fringes of the Bavarian capital to join a unit protecting a BMW factory producing aircraft engines.

Ratzinger insists he never took part in combat or fired a shot, because of a badly infected finger. He was later sent to Hungary where he set tank traps. In early 1944, he suddenly decided to leave his unit, knowing full well that SS units had orders to shoot deserters on sight. He recorded his terror when, after deserting his unit, he was stopped by other soldiers: "Thank God they were the ones who had enough of war and did not want to become murderers," he wrote in his memoirs.

Yet, in Traunstein, some of the town's older residents feel that questions about the Pope's early years remain unanswered. Herta Kaiser, an 83-year-old pensioner recalled that several people in the town hid Jews from the Nazis and helped them to escape to neutral Switzerland. "Traunstein was not all Nazi, it was also a Catholic stronghold," she said.

There is no evidence that the Ratzinger family felt inclined to help the town's few remaining Jews, or the smattering of anti-Nazi resistance fighters who dared to oppose the regime.

Elizabeth Lohner, 84, whose brother-in-law was sent to Dachau concentration camp for being a conscientious objector, recalled: "It was possible to resist and those people set an example for others." She added: "The Ratzingers were young and made different choices."

In 1937, another Traunstein family hid a local anti-Nazi resistance fighter, named Hans Braxenthaler. He had been tortured in Dachau for his opposition to the regime. Frieda Meyer, 82, one of the Ratzinger family's neighbours at the time, said: "When Braxenthaler was betrayed and the Nazis came for him, he shot himself rather than give himself up."

Ratzinger's election will also raise questions about the dubious role played by the Catholic Church during the Nazi era. The extent to which leading Catholics felt obliged to reach compromises with the regime is outlined by the stance taken by Ratzinger's mentor, Cardinal Michael von Faulhaber, one of the Pope's most important early influences.

Documented evidence shows that the cardinal visited Hitler's mountain retreat during the 1930s and was entertained to lunch by the Führer in person. During their meeting, Von Faulhaber is on record as telling Hitler that the Church saw him as an "authority chosen by God, to whom we owe respect".

Ratzinger was captured by US troops at war's end. He was taken to a field near the Bavarian town of Ulm where prisoners were being held and spent several weeks living in the open behind barbed wire. When he was released on 19 June 1945, he hitched a ride home to Traunstein on the back of a milk truck. "The following months of regained freedom, which we now had learned to value so much, belong to the happiest months of my life," he wrote in his memoirs.